Re: [PATCH 2/2] perf annotate-data: Ensure the number of type histograms

[Ian Rogers]

On Fri, May 10, 2024 at 2:04 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> Arnaldo reported that there is a case where nr_histograms and histograms
> don't agree each other.  It ended up in a segfault trying to access NULL
> histograms array.  Let's make sure to update the nr_histograms when the
> histograms array is changed.
>
> Reported-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/util/annotate-data.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
> index 57e7d4b3550b..965da6c0b542 100644
> --- a/tools/perf/util/annotate-data.c
> +++ b/tools/perf/util/annotate-data.c
> @@ -1800,7 +1800,6 @@ static int alloc_data_type_histograms(struct annotated_data_type *adt, int nr_en
>         sz += sizeof(struct type_hist_entry) * adt->self.size;
>
>         /* Allocate a table of pointers for each event */
> -       adt->nr_histograms = nr_entries;
>         adt->histograms = calloc(nr_entries, sizeof(*adt->histograms));
>         if (adt->histograms == NULL)
>                 return -ENOMEM;
> @@ -1814,6 +1813,8 @@ static int alloc_data_type_histograms(struct annotated_data_type *adt, int nr_en
>                 if (adt->histograms[i] == NULL)
>                         goto err;
>         }
> +
> +       adt->nr_histograms = nr_entries;
>         return 0;
>
>  err:
> @@ -1827,7 +1828,9 @@ static void delete_data_type_histograms(struct annotated_data_type *adt)
>  {
>         for (int i = 0; i < adt->nr_histograms; i++)
>                 zfree(&(adt->histograms[i]));
> +
>         zfree(&adt->histograms);
> +       adt->nr_histograms = 0;
>  }
>
>  void annotated_data_type__tree_delete(struct rb_root *root)
> --
> 2.45.0.118.g7fe29c98d7-goog
>